Method and apparatus for piercing blanking fuel pump diaphragms



June 3, 1969 w PARRENT ETAL 3,447,408

METHOD AND APPARATUS FOR PIERCING BLANKING FUEL PUMP DIAPHRAGMS FiledMarch 21, 1966 95 7187 j 30 i 47 I INVENTORSE ROBERT J. GRAY WILLIAMRUSSELL PARRENT ATTORNEY United States Patent 3,447,408 METHOD ANDAPPARATUS FOR PIERCING BLANKING FUEL PUMP DIAPHRAGMS William RussellParrent and Robert J. Gray, Fair-field,

111., assignors to Airtex Products, division of United IndustrialSyndicate, Inc., a corporation of New York Filed Mar. 21, 1966, Ser. No.541,903

Int. Cl. B26d 7/14, /08

U.S. CI. 83-21 7 Claims ABSTRACT OF THE DISCLOSURE A problem exists inthe assembly of fuel pumps having so-called loop diaphragms in that, dueto the loop in the rubberized sheet material generally referred to asdiaphragm cloth, the loop formation which may be effected in variousways causes an unevenness in the circular margin of the diaphragmsurrounding the loop in the circural margin of the diaphragm surroundingthe loop or arch. This unevenness is due to the fact that the arch isdrawn into the fuel chamber and the marginal surrounding area is clampedbetween flanges of the body castings of the fuel pump. The transition ofshape from arched condition causes wrinkles and leakage.

The present invention overcomes this drawback of the prior art byblanking and punching the diaphragm between forming dies in such amanner that diaphragm cloth is fed from a long strip or web to a pair ofmating dies which form the loop positively and uniformly in eachdiaphragm area to hold the diaphragm area in position corresponding tothe position it will occupy in an assembled pump. While so held, thediaphragm is blanked and pierced and the holes thus punched correspondto the hole position of the castings which take the threaded boltsduring assembly. Accordingly, by such piercing the holes are arranged ina perfect circle to mate with the casting holes while at the same timethe diaphragm cloth is positioned by the forming dies and the marginsurrounding the loop is held flat during piercing so as to eliminate orminimize any wrinkling effect when the diaphragm is assembled betweenthe pump castings.

Other objects and features of the invention will be apparent from thedescription that follows in which:

FIG. 1 is a vertical section in elevation of a compound blanking andpiercing die having loop forming dies and having blanking and punchingdies, for effecting the method of the invention;

FIG. 2 is a plan view of the upper head of the compound die;

FIG. 3 is an inverted plan view of the upper head of the compound die;and

FIG. 4 is a plan view showing a diaphragm blanked and punched aseffected by the apparatus of the invention and in accordance with themethod thereof, and being shown concentric in coaxial relation with atrue circle.

Referring to FIGS. 1-3, the bed of a stamping press is indicated by thereference character and it supports a lower forming die which coactswith an upper forming die 20. It will be noted that a loop or bight 23of an area of diaphragm cloth 26 is formed between the com- 3,447,408Patented June 3, 1969 "ice plementary formations of the forming dies 15and 20. Thus, the die 15 has a flat annular shoulder 15a coacting with aprotruding ridge 20a of die 20 to form the loop 23. It will beunderstood that diaphragm cloth in the form of a strip or web is fedfrom left to right between the dies, the die 20 being raised asuflicient distance by means of the press head 30 so as to effect a feedgap between the upper and lower forming dies.

The upper forming die 20 has a shoulder in the form of an annular flange33 which coacts with an inner annular flange 36 formed concentricallywithin a coacting cutting or blanking die 40. The aforementionedshoulders are normally biased against each other by means of springs 44socketed in the press head 30 and bearing outwardly against the uppersurface of the die 20. The coacting cutting die 40 is bolted as by bolts47 to the head 30. Accordingly, when the head is raised the shoulder 33is forced against the shoulder 36 by springs 44, which latter shoulderthen raises the die 20 in the course of upward movement of head 30.However, on downward movement of the head, assuming that an area ofdiaphragm cloth has been fed below die 20, not only will the loop 23 beformed but the marginal area of the material around the loop will beheld flat and gripped between the shoulder 50 of die 20 and the upperannular surface 53 of a die member 55 bolted by bolts 57 to the pressbed 10. In that manner the area of the cloth which is to be punched andblanked is securely held in a loop. Subsequent to the forming of theloop the cutting die 40 having the female cutting edge 60 blanks thediaphragm, the outer edge of die 55 being the male cutting edge. Atabout the same time a series of punches 65, arranged in a ring, punchholes in the clamped margin of the diaphragm area. The holes are forbolt passage when the diaphragm is assembled between the body castingsof a fuel pump in the usual manner. The die member 55 has tapering bores67 to effect a female die for punches 65, and to permit egress ofpunchings. Likewise, a centrally disposed punch 68 punches a hole incoaction with the female die bushing 71, such hole being for theactuating stem of the diaphragm to be secured in the central area. Thefemale die member 71 is carried as by force fit in the lower forming die15.

From the above description, it will be apparent that the lost motionprovided by the gap between shoulders 33 and 36 effect initially aforming of the diaphragm loop 23 by dies 15 and 20 followed by blankingof the diaphragm disc and punching of the holes.

The punches are carried in a plate 75 fastened as by bolts 78 to thehead 30.

A stripper plate 80 is carried on slidable pins 83 disposed in suitablebores in the bed 10 and a series of compression springs 86 bias plate 80upwardly so that its upper surface is initially level with the surfaceof the die 55. Thus, the heads of the bolts 83 move downwardly adistance corresponding to the gap 87 when the blanking die 40 pushesdownwardly in the course of cutting at the edge 60.

The lower forming die 15 may be carried as by force fit within the die55 or it may be bolted to the bed 10.

Various locating pins, such as pins 93 and 95, are utilized in aconventional manner for the purpose of accurately locatingthe severalcomponents to be boltedly assembled. A stop pin is carried in bed 10 toserve as a measuring device for each increment of cloth disposed in thedie.

Referring to FIG. 4, the effect of forming the loop in the diaphragmbetween the forming dies followed by subsequent blanking and punching isshown. It will be noted that a non-circular shape results as comparedwith the phantom line true circle. Thus, there is a deformation of thediaphragm area which results in slight flattening from a truly circularare at four edge portions or areas. This does not effect the operabilityof the diaphragm when assembled in a pump but enhances the forming ofthe loop in the course of assembly with the pump castings. Thus, thediaphragm may be put between the body castings with the holes inregister therewith and the diaphragm stem pushed down after which thebolts are inserted and tightened with the diaphragm stem in downwardposition, that is, in the position it would have at the end of adischarge stroke.

The particular mode of assembly just described is not the only one whichcould be used, but is merely set forth for illustrative purposes.

FIG. 4 shows four flattened areas for a diaphragm, this being thecondition which obtains for one type of commercial fuel pump; other pumptypes which may use diaphragms of dilferent diameter, thickness and moreor less holes might have more or less than four edge portions ofdecreased arcuateness. The phantom line circle in FIG. 4 can beconsidered as representing the cutting edge of the blanking die, thematerial of the diaphragm being circumscribed thereby.

We claim:

1. A method of piercing and blanking loop type diaphragms whichcomprises clamping an area of diaphragm cloth in sheet form out of itsnormal plane into a loop configuration corresponding generally to theconfiguration of the diaphragm when assembled in a fuel pump, andblanking the area with a circular die and punching the margin of thearea to provide bolt holes therethrough adjacent the periphery thereof,wherein the resulting separated diaphragm is essentially non-circular inperimeter and wherein the holes therethrough are essentially located ina circle.

2. A method as set forth in claim 1, including punching a hole centrallyof the clamped area for accommodating a fuel pump stem.

3. A method of preparing diaphragms from sheet material and having abight formation when assembled in a fuel pump which comprises effectinga bight formation in a piece of diaphragm cloth out of its normal plane,holding a marginal area surrounding said formation in clamped condition,punching a series of holes around said formation in said marginal areain position to register with bolt holes of a fuel pump casting in whichsaid diaphragm is to be assembled.

4. A method as set forth in claim 3, including the step of blanking saiddiaphragm to separate it from material surrounding said holes.

5. An apparatus for blanking and piercing fuel pump diaphragms of thetype having a loop formation which comprises upper and lower loopforming dies between which an area of diaphragm cloth is clamped toeffect an annular loop configuration out of the plane of said cloth, ablanking die surrounding one of said latter dies and a plurality ofpunches disposed interiorly of said blanking die.

6. An apparatus as set forth in claim 5, wherein said blanking die andone of said forming dies have abuttable shoulders, a moveable die head,said blanking die being integrally secured thereto, spring meansintermediate said upper forming die and said die head for normallyeffecting abutment of said shoulders, whereby when said upper formingdie clamps diaphragm cloth between itself and said lower die saidshoulders move relative to each other by compressing said spring meansand said blanking die severs the diaphragm area from said cloth.

7. In an apparatus as set forth in claim 6, said plurality of punchesbeing carried by said movable die head, said upper forming die havingbores through which said punches are slidable to engage the diaphragmarea for punching holes in the diaphragm cloth.

References Cited UNITED STATES PATENTS 124,669 3/ 1872 Delkescamp 83211,746,043 2/1930 Maguire 83-637 X 2,100,683 11/1937 Bierwirth 83-621 X3,234,774 2/ 1966 Margedant.

ANDREW R. JUHASZ, Primary Examiner.

US. Cl. X.R. 83-176, 6 21

